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Article
AGB star intershell abundances inferred from UV spectra of extremely hot post-AGB stars
The hydrogen-deficiency in extremely hot post-AGB stars of spectral class PG1159 is probably caused by a (very) late helium-shell flash or a AGB final thermal pulse that consumes the hydrogen envelope, exposin...
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Article
FUV spectroscopy of the central star of the planetary nebula Sh 2–216
The far-ultraviolet (FUV) spectrum of LS V +46°21, the central star (CS) of the planetary nebula (PN) Sh 2−216, is strongly contaminated by interstellar absorption and thus, we have to simultaneously model bot...
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Chapter and Conference Paper
PRIME: A Deep Near-Infrared Survey Project
PRIME is a proposed space mission for a deep survey of 25% to 100% of the sky in four near-IR bands (0.9-3.5 μm), to M AB ...
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Chapter
Abundance Patterns in Hot DA Atmospheres from FUSE
FUSE since its launch on June 24, 1999 has already observed well over 80 hot white dwarfs. This sample encompasses a wide range of effective temperatures and surface gravities, which makes it ide...
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Chapter
A New Determination of the Spectroscopic Mass and Radius for Sirius B
We have obtained a very high quality spectrum of the white dwarf Sirius B with the Far Ultraviolet Spectroscopic Explorer (FUSE). The H I Lyman series from Ly β through Ly 10 is evident, as are the quasi-molecula...
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Chapter
FUSE Observations of the DAO White Dwarf Feige 55
The star Feige 55 is a spectroscopic binary consisting of a metal-rich DAO white dwarf and an unseen degenerate companion, with an orbital period of approximately 1.5 days. This star has been observed at sever...
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Chapter
The FUSE Spectrum of the DB White Dwarf GD 190
At V = 14.65, GD 190 is a fairly bright classical DB star with an effective temperature slightly above 20,000 K. Its optical spectrum, characterized by strong He I lines, was the first one observed to show the fo...
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Chapter
FUSE Spectroscopy of the Two Prototype White Dwarfs with Signatures of a Super-Hot Wind
The O VIII phenomenon describes the occurrence of ultra-high ionization absorption lines of the CNO elements (e.g. O VIII, N VII, C VI, and even Ne X) in the optical spectra hot of DO WDs. This requires temper...
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Chapter
Analysis Of Fuse and IUE Spectra of the SDOB Star EC11481-2303
SdOB stars are associated with the extreme horizontal branch (EHB). They by-pass AGB evolution because of their low H-envelope mass and they may be progenitors of white dwarfs with peculiar chemical abundances...
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Chapter
Metal Abundances in PG1159 Stars from Chandra and Fuse Spectroscopy
We investigate FUSE spectra of three PG1159 stars and do not find any evidence for iron lines. From a comparison with NLTE models we conclude a deficiency of 1–1.5 dex. We speculate that iron was transformed i...
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Chapter
FUSE Spectra of DO White Dwarfs
DO white dwarfs are hot helium-rich white dwarfs which populate the white dwarf cooling sequence from the hot beginning (Teff=120 000K) down to 45000K. At this temperature the helium-rich cooling sequence is inte...
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Article
Test of the decaying dark matter hypothesis using the Hopkins Ultraviolet Telescope
SCIAMA has argued1–4 that the dark matter associated with galaxies, clusters of galaxies and the intergalactic medium consists of τ neutrinos of rest mass 28–30 eV, whose decay generates ultraviolet photons of en...
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Chapter and Conference Paper
The creation of high energy densities with antimatter beams
The use of antiprotons (and antideuterons) for the study of the behavior of nuclear matter at high energy density is considered. It is shown that high temperatures and high energy densities can be achieved for...
